We calculate the gravitational-wave spectra produced by the electroweak phase transition with TeV-scale Beyond-Standard-Model physics in the early universe. Our study captures the effect of quantum and thermal fluctuations within a non-perturbative framework. We discover a universal relation between the mean bubble separation and the strength parameter of the phase transition, which holds for a wide range of new-physics contributions. The ramifications of this result are three-fold: first, they constrain the gravitational-wave spectra resulting from heavy (TeV-scale) new physics. Second, they contribute to distinguishing heavy from light new physics directly from the gravitational-wave signature. Third, they suggest that a concerted effort of gravitational-wave observations together with collider experiments could be required to distinguish between different models of heavy new physics.
A. Eichhorn, J. Lumma, J. M. Pawlowski, M. Reichert, M. Yamada, “Universal gravitationalwave signatures from heavy new physics in the electroweak sector”, JCAP 05, 006 (2021).
Related to Project: A02